/* Copyright (c) 2001-2011, The HSQL Development Group
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * Neither the name of the HSQL Development Group nor the names of its
 * contributors may be used to endorse or promote products derived from this
 * software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL HSQL DEVELOPMENT GROUP, HSQLDB.ORG,
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */


package org.hsqldb.jdbc;

import java.sql.BatchUpdateException;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.SQLWarning;
import java.sql.Statement;

import org.hsqldb.HsqlException;
import org.hsqldb.StatementTypes;
import org.hsqldb.navigator.RowSetNavigator;
import org.hsqldb.result.Result;
import org.hsqldb.result.ResultConstants;
import org.hsqldb.result.ResultProperties;

/* $Id: JDBCStatement.java 5283 2013-09-29 17:52:44Z unsaved $ */

// fredt@users   20020320 - patch 1.7.0 - JDBC 2 support and error trapping
//
// JDBC 2 methods can now be called from jdk 1.1.x - see javadoc comments
// SCROLL_INSENSITIVE and FORWARD_ONLY types for ResultSet are now supported
//
// boucherb@users 20020509 - added "throws SQLException" to all methods where
//                           it was missing here but specified in the
//                           java.sql.Statement interface,
//                           updated generic documentation to JDK 1.4, and
//                           added JDBC3 methods and docs
// boucherb &     20020505 - extensive review and update of docs and behaviour
// fredt@users               to comply with java.sql specification
// fredt@users    20030620 - patch 1.7.2 - rewritten and simplified
// boucherb@users 200404xx - javadoc updates toward 1.7.2 final
// boucherb@users 20051207 - patch 1.8.0.x initial JDBC 4.0 support work
// boucherb@users 20060522 - doc   1.9.0 full synch up to Mustang Build 84
// Revision 1.16  2006/07/12 12:40:59  boucherb
// patch 1.9.0
// - full synch up to Mustang b90

/**
 * <!-- start generic documentation -->
 * <P>The object used for executing a static SQL statement
 * and returning the results it produces.
 * <P>
 * By default, only one <code>ResultSet</code> object per <code>Statement</code>
 * object can be open at the same time. Therefore, if the reading of one
 * <code>ResultSet</code> object is interleaved
 * with the reading of another, each must have been generated by
 * different <code>Statement</code> objects. All execution methods in the
 * <code>Statement</code> interface implicitly close a statment's current
 * <code>ResultSet</code> object if an open one exists.
 * <!-- end generic documentation-->
 *
 * <!-- start release-specific documentation -->
 * <div class="ReleaseSpecificDocumentation">
 * <h3>HSQLDB-Specific Information:</h3><p>
 * From version 2.0, the implementation meets the JDBC specification
 * requirment that any existing ResultSet is closed when execute() or
 * executeQuery() methods are called. The connection property close_result=true
 * is required for this behaviour.
 * <p>
 *
 * <b>JRE 1.1.x Notes:</b> <p>
 *
 * In general, JDBC 2 support requires Java 1.2 and above, and JDBC3 requires
 * Java 1.4 and above. In HSQLDB, support for methods introduced in different
 * versions of JDBC depends on the JDK version used for compiling and building
 * HSQLDB.<p>
 *
 * Since 1.7.0, all JDBC 2 methods can be called while executing under the
 * version 1.1.x
 * <em>Java Runtime Environment</em><sup><font size="-2">TM</font></sup>.
 * However, in addition to this technique requiring explicit casts to the
 * org.hsqldb.jdbc.* classes, some of these method calls require
 * <code>int</code> values that are defined only in the JDBC 2 or greater
 * version of the {@link ResultSet ResultSet} interface.  For this
 * reason these values are defined in {@link JDBCResultSet JDBCResultSet}.<p>
 *
 * In a JRE 1.1.x environment, calling JDBC 2 methods that take or return the
 * JDBC2-only <code>ResultSet</code> values can be achieved by referring
 * to them in parameter specifications and return value comparisons,
 * respectively, as follows: <p>
 *
 * <pre class="JavaCodeExample">
 * JDBCResultSet.FETCH_FORWARD
 * JDBCResultSet.TYPE_FORWARD_ONLY
 * JDBCResultSet.TYPE_SCROLL_INSENSITIVE
 * JDBCResultSet.CONCUR_READ_ONLY
 * //etc.
 * </pre> <p>
 *
 * However, please note that code written to use HSQLDB JDBC 2 features under
 * JDK 1.1.x will not be compatible for use with other JDBC 2 drivers. Please
 * also note that this feature is offered solely as a convenience to developers
 * who must work under JDK 1.1.x due to operating constraints, yet wish to
 * use some of the more advanced features available under the JDBC 2
 * specification. <p>
 *
 * (fredt@users)<br>
 * (boucherb@users)<p>
 *
 * </div>
 * <!-- end release-specific documentation -->
 *
 * @author Campbell Boucher-Burnet (boucherb@users dot sourceforge.net)
 * @author Fred Toussi (fredt@users dot sourceforge.net)
 * @version 2.3.0
 * @revised JDK 1.6, HSQLDB 2.0
 * @see JDBCConnection#createStatement
 * @see JDBCResultSet
 */
//#ifdef JAVA6
public class JDBCStatement extends JDBCStatementBase implements Statement,
        java.sql.Wrapper {

//#else
/*
public class JDBCStatement extends JDBCStatementBase implements Statement {
*/

//#endif JAVA6

    /**
     * <!-- start generic documentation -->
     * Executes the given SQL statement, which returns a single
     * <code>ResultSet</code> object.
     * <!-- end generic documentation -->
     *
     * <!-- start release-specific documentation -->
     * <div class="ReleaseSpecificDocumentation">
     * <h3>HSQLDB-Specific Information:</h3> <p>
     *
     * This method should not be used for statements other than SELECT queries.<p>
     *
     * From 2.0, HSQLDB throws an exception when the statement
     * is a DDL statement or an UPDATE or DELETE statement.
     * </div>
     * <!-- end release-specific documentation -->
     *
     * @param sql an SQL statement to be sent to the database, typically a
     *        static SQL <code>SELECT</code> statement
     * @return a <code>ResultSet</code> object that contains the data produced
     *         by the given query; never <code>null</code>
     * @exception SQLException if a database access error occurs,
     * this method is called on a closed <code>Statement</code> or the given
     *            SQL statement produces anything other than a single
     *            <code>ResultSet</code> object
     */
    public synchronized ResultSet executeQuery(
            String sql) throws SQLException {

        fetchResult(sql, StatementTypes.RETURN_RESULT,
                    JDBCStatementBase.NO_GENERATED_KEYS, null, null);

        return getResultSet();
    }

    /**
     * <!-- start generic documentation -->
     * Executes the given SQL statement, which may be an <code>INSERT</code>,
     * <code>UPDATE</code>, or <code>DELETE</code> statement or an
     * SQL statement that returns nothing, such as an SQL DDL statement.
     * <!-- end generic documentation -->
     *
     * @param sql (JDBC4 clarification:) an SQL Data Manipulation Language (DML) statement, such as <code>INSERT</code>, <code>UPDATE</code> or
     * <code>DELETE</code>; or an SQL statement that returns nothing,
     * such as a DDL statement.
     *
     * @return (JDBC4 clarification:) either (1) the row count for SQL Data Manipulation Language (DML) statements
     *         or (2) 0 for SQL statements that return nothing
     *
     * @exception SQLException if a database access error occurs,
     * this method is called on a closed <code>Statement</code> or the given
     *            SQL statement produces a <code>ResultSet</code> object
     */
    public synchronized int executeUpdate(String sql) throws SQLException {

        fetchResult(sql, StatementTypes.RETURN_COUNT,
                    JDBCStatementBase.NO_GENERATED_KEYS, null, null);

        return resultIn.getUpdateCount();
    }

    /**
     * <!-- start generic documentation -->
     * Releases this <code>Statement</code> object's database
     * and JDBC resources immediately instead of waiting for
     * this to happen when it is automatically closed.
     * It is generally good practice to release resources as soon as
     * you are finished with them to avoid tying up database
     * resources.
     * <P>
     * Calling the method <code>close</code> on a <code>Statement</code>
     * object that is already closed has no effect.
     * <P>
     * <B>Note:</B>When a <code>Statement</code> object is
     * closed, its current <code>ResultSet</code> object, if one exists, is
     * also closed.
     * (JDBC4 deleted:) [A <code>Statement</code> object is
     * automatically closed when it is garbage collected.]
     * <!-- end generic documentation -->
     *
     * @exception SQLException if a database access error occurs
     */
    public synchronized void close() throws SQLException {

        if (isClosed) {
            return;
        }
        closeResultData();

        batchResultOut = null;
        connection     = null;
        resultIn       = null;
        resultOut      = null;
        isClosed       = true;
    }

    //----------------------------------------------------------------------

    /**
     * <!-- start generic documentation -->
     * Retrieves the maximum number of bytes that can be
     * returned for character and binary column values in a <code>ResultSet</code>
     * object produced by this <code>Statement</code> object.
     * This limit applies only to  <code>BINARY</code>, <code>VARBINARY</code>,
     * <code>LONGVARBINARY</code>, <code>CHAR</code>, <code>VARCHAR</code>,
     * (JDBC4 new:) <code>NCHAR</code>, <code>NVARCHAR</code>, <code>LONGNVARCHAR</code>
     * and <code>LONGVARCHAR</code> columns.  If the limit is exceeded, the
     * excess data is silently discarded.
     * <!-- end generic documentation -->
     *
     * <!-- start release-specific documentation -->
     * <div class="ReleaseSpecificDocumentation">
     * <h3>HSQLDB-Specific Information:</h3> <p>
     *
     * Including 1.7.2, HSQLDB always returns zero, meaning there
     * is no limit.
     * </div>
     * <!-- end release-specific documentation -->
     *
     * @return the current column size limit for columns storing character and
     *         binary values; zero means there is no limit
     * @exception SQLException if a database access error occurs or
     * this method is called on a closed <code>Statement</code>
     * @see #setMaxFieldSize
     */
    public synchronized int getMaxFieldSize() throws SQLException {

        checkClosed();

        return 0;
    }

    /**
     * <!-- start generic documentation -->
     * (JDBC4 clarification:) Sets the limit for the maximum number of bytes in a <code>ResultSet</code>
     * Sets the limit for the maximum number of bytes that can be returned for
     * character and binary column values in a <code>ResultSet</code>
     * object produced by this <code>Statement</code> object.
     *
     * This limit applies
     * only to <code>BINARY</code>, <code>VARBINARY</code>,
     * <code>LONGVARBINARY</code>, <code>CHAR</code>, <code>VARCHAR</code>,
     * (JDBC4 new:) <code>NCHAR</code>, <code>NVARCHAR</code>, <code>LONGNVARCHAR</code> and
     * <code>LONGVARCHAR</code> fields.  If the limit is exceeded, the excess data
     * is silently discarded. For maximum portability, use values
     * greater than 256.
     * <!-- emd generic documentation -->
     *
     * <!-- start release-specific documentation -->
     * <div class="ReleaseSpecificDocumentation">
     * <h3>HSQLDB-Specific Information:</h3> <p>
     *
     * To present, calls to this method are simply ignored; HSQLDB always
     * stores the full number of bytes when dealing with any of the field types
     * mentioned above. These types all have an absolute maximum element upper
     * bound determined by the Java array index limit
     * java.lang.Integer.MAX_VALUE.  For XXXBINARY types, this translates to
     * Integer.MAX_VALUE bytes.  For XXXCHAR types, this translates to
     * 2 * Integer.MAX_VALUE bytes (2 bytes / character). <p>
     *
     * In practice, field sizes are limited to values much smaller than the
     * absolute maximum element upper bound, in particular due to limits imposed
     * on the maximum available Java heap memory.
     * </div>
     * <!-- end release-specific documentation -->
     *
     * @param max the new column size limit in bytes; zero means there is no limit
     * @exception SQLException if a database access error occurs,
     * this method is called on a closed <code>Statement</code>
     *            or the condition max >= 0 is not satisfied
     * @see #getMaxFieldSize
     */
    public void setMaxFieldSize(int max) throws SQLException {

        checkClosed();

        if (max < 0) {
            throw JDBCUtil.outOfRangeArgument();
        }
    }

    /**
     * <!-- start generic documentation -->
     * Retrieves the maximum number of rows that a
     * <code>ResultSet</code> object produced by this
     * <code>Statement</code> object can contain.  If this limit is exceeded,
     * the excess rows are silently dropped.
     * <!-- start generic documentation -->
     *
     * @return the current maximum number of rows for a <code>ResultSet</code>
     *         object produced by this <code>Statement</code> object;
     *         zero means there is no limit
     * @exception SQLException if a database access error occurs or
     * this method is called on a closed <code>Statement</code>
     * @see #setMaxRows
     */
    public synchronized int getMaxRows() throws SQLException {

        checkClosed();

        return maxRows;
    }

    /**
     * <!-- start generic documentation -->
     * (JDBC4 clarification:)
     * Sets the limit for the maximum number of rows that any
     * <code>ResultSet</code> object  generated by this <code>Statement</code>
     * object can contain to the given number.
     * If the limit is exceeded, the excess
     * rows are silently dropped.
     * <!-- end generic documentation -->
     *
     * @param max the new max rows limit; zero means there is no limit
     * @exception SQLException if a database access error occurs,
     * this method is called on a closed <code>Statement</code>
     *            or the condition max >= 0 is not satisfied
     * @see #getMaxRows
     */
    public synchronized void setMaxRows(int max) throws SQLException {

        checkClosed();

        if (max < 0) {
            throw JDBCUtil.outOfRangeArgument();
        }
        maxRows = max;
    }

    /**
     * <!-- start generic documentation -->
     * Sets escape processing on or off.
     * If escape scanning is on (the default), the driver will do
     * escape substitution before sending the SQL statement to the database.
     *
     * Note: Since prepared statements have usually been parsed prior
     * to making this call, disabling escape processing for
     * <code>PreparedStatements</code> objects will have no effect.
     * <!-- end generic documentation -->
     *
     * @param enable <code>true</code> to enable escape processing;
     *       <code>false</code> to disable it
     * @exception SQLException if a database access error occurs or
     * this method is called on a closed <code>Statement</code>
     */
    public void setEscapeProcessing(boolean enable) throws SQLException {

        checkClosed();

        isEscapeProcessing = enable;
    }

    /**
     * <!-- start generic documentation -->
     * Retrieves the number of seconds the driver will
     * wait for a <code>Statement</code> object to execute.
     * If the limit is exceeded, a
     * <code>SQLException</code> is thrown.
     * <!-- end generic documentation -->
     *
     * <!-- start release-specific documentation -->
     * <div class="ReleaseSpecificDocumentation">
     * <h3>HSQLDB-Specific Information:</h3> <p>
     *
     * To present, HSQLDB always returns zero, meaning there
     * is no limit.
     * </div>
     * <!-- end release-specific documentation -->
     *
     * @return the current query timeout limit in seconds; zero means there is
     *         no limit
     * @exception SQLException if a database access error occurs or
     * this method is called on a closed <code>Statement</code>
     * @see #setQueryTimeout
     */
    public synchronized int getQueryTimeout() throws SQLException {

        checkClosed();

        return queryTimeout;
    }

    /**
     * <!-- start generic documentation -->
     * Sets the number of seconds the driver will wait for a
     * <code>Statement</code> object to execute to the given number of seconds.
     * If the limit is exceeded, an <code>SQLException</code> is thrown. A JDBC
     * (JDBC4 clarification:)
     * driver must apply this limit to the <code>execute</code>,
     * <code>executeQuery</code> and <code>executeUpdate</code> methods. JDBC driver
     * implementations may also apply this limit to <code>ResultSet</code> methods
     * (consult your driver vendor documentation for details).
     * <!-- end generic documentation -->
     *
     * <!-- start release-specific documentation -->
     * <div class="ReleaseSpecificDocumentation">
     * <h3>HSQLDB-Specific Information:</h3> <p>
     *
     * The maximum number of seconds to wait is 32767.
     * </div>
     * <!-- end release-specific documentation -->
     *
     * @param seconds the new query timeout limit in seconds; zero means
     *        there is no limit
     * @exception SQLException if a database access error occurs,
     * this method is called on a closed <code>Statement</code>
     *            or the condition seconds >= 0 is not satisfied
     * @see #getQueryTimeout
     */
    public void setQueryTimeout(int seconds) throws SQLException {

        checkClosed();

        if (seconds < 0) {
            throw JDBCUtil.outOfRangeArgument();
        }

        if (seconds > Short.MAX_VALUE) {
            seconds = Short.MAX_VALUE;
        }
        queryTimeout = seconds;
    }

    /**
     * <!-- start generic documentation -->
     * Cancels this <code>Statement</code> object if both the DBMS and
     * driver support aborting an SQL statement.
     * This method can be used by one thread to cancel a statement that
     * is being executed by another thread.
     * <!-- end generic documentation -->
     *
     * <!-- start release-specific documentation -->
     * <div class="ReleaseSpecificDocumentation">
     * <h3>HSQLDB-Specific Information:</h3> <p>
     *
     * Including 2.0, HSQLDB does <i>not</i> support aborting an SQL
     * statement; calls to this method are ignored.
     * </div>
     * <!-- end release-specific documentation -->
     *
     * @exception SQLException if a database access error occurs or
     * this method is called on a closed <code>Statement</code>
     * @exception SQLFeatureNotSupportedException if the JDBC driver does not support
     * this method
     */
    public synchronized void cancel() throws SQLException {
        checkClosed();
    }

    /**
     * <!-- start generic documentation -->
     * Retrieves the first warning reported by calls on this <code>Statement</code> object.
     * Subsequent <code>Statement</code> object warnings will be chained to this
     * <code>SQLWarning</code> object.
     *
     * <p>The warning chain is automatically cleared each time
     * a statement is (re)executed. This method may not be called on a closed
     * <code>Statement</code> object; doing so will cause an <code>SQLException</code>
     * to be thrown.
     *
     * <P><B>Note:</B> If you are processing a <code>ResultSet</code> object, any
     * warnings associated with reads on that <code>ResultSet</code> object
     * will be chained on it rather than on the <code>Statement</code>
     * object that produced it.
     * <!-- end generic documentation -->
     *
     * <!-- start release-specific documentation -->
     * <div class="ReleaseSpecificDocumentation">
     * <h3>HSQLDB-Specific Information:</h3> <p>
     *
     * In 2.0, HSQLDB may produces Statement warnings;
     * this method always returns null.
     * </div>
     * <!-- end release-specific documentation -->
     *
     * @return the first <code>SQLWarning</code> object or <code>null</code>
     *         if there are no warnings
     * @exception SQLException if a database access error occurs or
     * this method is called on a closed <code>Statement</code>
     */
    public synchronized SQLWarning getWarnings() throws SQLException {

        checkClosed();

        return rootWarning;
    }

    /**
     * <!-- start generic documentation -->
     * Clears all the warnings reported on this <code>Statement</code>
     * object. After a call to this method,
     * the method <code>getWarnings</code> will return
     * <code>null</code> until a new warning is reported for this
     * <code>Statement</code> object.
     * <!-- end generic documentation -->
     *
     * <!-- start release-specific documentation -->
     * <div class="ReleaseSpecificDocumentation">
     * <h3>HSQLDB-Specific Information:</h3> <p>
     *
     * In HSQLDB 2.0, <code>SQLWarning</code> objects may
     * be produced for Statement Objects; calls to this method clear the warnings.
     * </div>
     * <!-- end release-specific documentation -->
     *
     * @exception SQLException if a database access error occurs or
     * this method is called on a closed <code>Statement</code>
     */
    public synchronized void clearWarnings() throws SQLException {

        checkClosed();

        rootWarning = null;
    }

    /** @todo 1.9.0 - implement */

    /**
     * <!-- start generic documentation -->
     * Sets the SQL cursor name to the given <code>String</code>, which
     * will be used by subsequent <code>Statement</code> object
     * <code>execute</code> methods. This name can then be
     * used in SQL positioned update or delete statements to identify the
     * current row in the <code>ResultSet</code> object generated by this
     * statement.  If the database does not support positioned update/delete,
     * this method is a noop.  To insure that a cursor has the proper isolation
     * level to support updates, the cursor's <code>SELECT</code> statement
     * should have the form <code>SELECT FOR UPDATE</code>.  If
     * <code>FOR UPDATE</code> is not present, positioned updates may fail.
     *
     * <P><B>Note:</B> By definition, the execution of positioned updates and
     * deletes must be done by a different <code>Statement</code> object than
     * the one that generated the <code>ResultSet</code> object being used for
     * positioning. Also, cursor names must be unique within a connection.
     * <!-- end generic documentation -->
     *
     * <!-- start release-specific documentation -->
     * <div class="ReleaseSpecificDocumentation">
     * <h3>HSQLDB-Specific Information:</h3> <p>
     *
     * Including 2.0, HSQLDB does not support named cursors;
     * calls to this method are ignored.
     * </div>
     * <!-- end release-specific documentation -->
     *
     * @param name the new cursor name, which must be unique within
     *             a connection
     * @exception SQLException if a database access error occurs or
     * this method is called on a closed <code>Statement</code>
     * @throws SQLFeatureNotSupportedException  if the JDBC driver does not support this method
     */
    public void setCursorName(String name) throws SQLException {
        checkClosed();
    }

    //----------------------- Multiple Results --------------------------

    /**
     * <!-- start generic documentation -->
     * Executes the given SQL statement, which may return multiple results.
     * In some (uncommon) situations, a single SQL statement may return
     * multiple result sets and/or update counts.  Normally you can ignore
     * this unless you are (1) executing a stored procedure that you know may
     * return multiple results or (2) you are dynamically executing an
     * unknown SQL string.
     * <P>
     * The <code>execute</code> method executes an SQL statement and indicates the
     * form of the first result.  You must then use the methods
     * <code>getResultSet</code> or <code>getUpdateCount</code>
     * to retrieve the result, and <code>getMoreResults</code> to
     * move to any subsequent result(s).
     * <!-- end generic documentation -->
     *
     * @param sql any SQL statement
     * @return <code>true</code> if the first result is a <code>ResultSet</code>
     *         object; <code>false</code> if it is an update count or there are
     *         no results
     * @exception SQLException if a database access error occurs or
     * this method is called on a closed <code>Statement</code>
     * @see #getResultSet
     * @see #getUpdateCount
     * @see #getMoreResults
     */
    public synchronized boolean execute(String sql) throws SQLException {

        fetchResult(sql, StatementTypes.RETURN_ANY,
                    JDBCStatementBase.NO_GENERATED_KEYS, null, null);

        return currentResultSet != null;
    }

    /**
     * <!-- start generic documentation -->
     *  Retrieves the current result as a <code>ResultSet</code> object.
     *  This method should be called only once per result.
     * <!-- end generic documentation -->
     *
     * <!-- start release-specific documentation -->
     * <div class="ReleaseSpecificDocumentation">
     * <h3>HSQLDB-Specific Information:</h3> <p>
     *
     * </div>
     * <!-- end release-specific documentation -->
     *
     * @return the current result as a <code>ResultSet</code> object or
     * <code>null</code> if the result is an update count or there are no more results
     * @exception SQLException if a database access error occurs or
     * this method is called on a closed <code>Statement</code>
     * @see #execute
     */
    public synchronized ResultSet getResultSet() throws SQLException {
        return super.getResultSet();
    }

    /**
     * <!-- start generic documentation -->
     *  Retrieves the current result as an update count;
     *  if the result is a <code>ResultSet</code> object or there are no more results, -1
     *  is returned. This method should be called only once per result.
     * <!-- end generic documentation -->
     *
     * @return the current result as an update count; -1 if the current result is a
     * <code>ResultSet</code> object or there are no more results
     * @exception SQLException if a database access error occurs or
     * this method is called on a closed <code>Statement</code>
     * @see #execute
     */
    public synchronized int getUpdateCount() throws SQLException {
        return super.getUpdateCount();
    }

    /**
     * <!-- start generic documentation -->
     * Moves to this <code>Statement</code> object's next result, returns
     * <code>true</code> if it is a <code>ResultSet</code> object, and
     * implicitly closes any current <code>ResultSet</code>
     * object(s) obtained with the method <code>getResultSet</code>.
     *
     * <P>There are no more results when the following is true:
     * <PRE>
     *     // stmt is a Statement object
     *     ((stmt.getMoreResults() == false) && (stmt.getUpdateCount() == -1))
     * </PRE>
     * <!-- end generic documentation -->
     *
     * @return <code>true</code> if the next result is a <code>ResultSet</code>
     *         object; <code>false</code> if it is an update count or there are
     *         no more results
     * @exception SQLException if a database access error occurs or
     * this method is called on a closed <code>Statement</code>
     * @see #execute
     */
    public synchronized boolean getMoreResults() throws SQLException {
        return getMoreResults(JDBCStatementBase.CLOSE_CURRENT_RESULT);
    }

    //--------------------------JDBC 2.0-----------------------------

    /**
     * <!-- start generic documentation -->
     * Gives the driver a hint as to the direction in which
     * rows will be processed in <code>ResultSet</code>
     * objects created using this <code>Statement</code> object.  The
     * default value is <code>ResultSet.FETCH_FORWARD</code>.
     * <P>
     * Note that this method sets the default fetch direction for
     * result sets generated by this <code>Statement</code> object.
     * Each result set has its own methods for getting and setting
     * its own fetch direction.
     * <!-- end generic documentation -->
     *
     * <!-- start release-specific documentation -->
     * <div class="ReleaseSpecificDocumentation">
     * <h3>HSQLDB-Specific Information:</h3> <p>
     *
     * HSQLDB accepts all valid parameters. <p>
     * <!-- end release-specific documentation -->
     *
     * @param direction the initial direction for processing rows
     * @exception SQLException if a database access error occurs,
     * this method is called on a closed <code>Statement</code>
     * or the given direction
     * is not one of <code>ResultSet.FETCH_FORWARD</code>,
     * <code>ResultSet.FETCH_REVERSE</code>, or <code>ResultSet.FETCH_UNKNOWN</code>
     * @since JDK 1.2 (JDK 1.1.x developers: read the overview
     *    for JDBCStatement)
     * @see #getFetchDirection
     */
    public synchronized void setFetchDirection(
            int direction) throws SQLException {

        checkClosed();
        checkClosed();

        switch (direction) {

            case JDBCResultSet.FETCH_FORWARD :
            case JDBCResultSet.FETCH_REVERSE :
            case JDBCResultSet.FETCH_UNKNOWN :
                fetchDirection = direction;

                break;
            default :
                throw JDBCUtil.invalidArgument();
        }
    }

    /**
     * <!-- start generic documentation -->
     * Retrieves the direction for fetching rows from
     * database tables that is the default for result sets
     * generated from this <code>Statement</code> object.
     * If this <code>Statement</code> object has not set
     * a fetch direction by calling the method <code>setFetchDirection</code>,
     * the return value is implementation-specific.
     * <!-- end generic documentation -->
     *
     * <!-- start release-specific documentation -->
     * <div class="ReleaseSpecificDocumentation">
     * <h3>HSQLDB-Specific Information:</h3> <p>
     *
     * HSQLDB returns the fetch direction. <p>
     * </div>
     * <!-- end release-specific documentation -->
     *
     * @return the default fetch direction for result sets generated
     *          from this <code>Statement</code> object
     * @exception SQLException if a database access error occurs or
     * this method is called on a closed <code>Statement</code>
     * @since JDK 1.2 (JDK 1.1.x developers: read the overview
     *    for JDBCStatement)
     * @see #setFetchDirection
     */
    public int getFetchDirection() throws SQLException {

        checkClosed();

        return this.fetchDirection;
    }

    /**
     * <!-- start generic documentation -->
     * (JDBC4 clarification:)
     * Gives the JDBC driver a hint as to the number of rows that should
     * be fetched from the database when more rows are needed for
     * <code>ResultSet</code> objects genrated by this <code>Statement</code>.
     * If the value specified is zero, then the hint is ignored.
     * The default value is zero.
     * <!-- start generic documentation -->
     *
     * <!-- start release-specific documentation -->
     * <div class="ReleaseSpecificDocumentation">
     * <h3>HSQLDB-Specific Information:</h3> <p>
     *
     * HSQLDB uses the specified value as a hint, but may process more or fewer
     * rows than specified.
     * </div>
     * <!-- end release-specific documentation -->
     *
     * @param rows the number of rows to fetch
     * @exception SQLException if a database access error occurs,
     * this method is called on a closed <code>Statement</code> or the
     *        (JDBC4 modified:)
     *        condition  <code>rows >= 0</code> is not satisfied.
     * @since JDK 1.2 (JDK 1.1.x developers: read the overview
     *   for JDBCStatement)
     * @see #getFetchSize
     */
    public synchronized void setFetchSize(int rows) throws SQLException {

        checkClosed();

        if (rows < 0) {
            throw JDBCUtil.outOfRangeArgument();
        }
        fetchSize = rows;
    }

    /**
     * <!-- start generic documentation -->
     * Retrieves the number of result set rows that is the default
     * fetch size for <code>ResultSet</code> objects
     * generated from this <code>Statement</code> object.
     * If this <code>Statement</code> object has not set
     * a fetch size by calling the method <code>setFetchSize</code>,
     * the return value is implementation-specific.
     * <!-- end generic documentation -->
     *
     * <!-- start release-specific documentation -->
     * <div class="ReleaseSpecificDocumentation">
     * <b>HSQLDB-Specific Information</b> <p>
     *
     * HSQLDB returns 0 by default, or the fetch size specified by setFetchSize
     * </div>
     * <!-- end release-specific documentation -->
     *
     * @return the default fetch size for result sets generated
     *          from this <code>Statement</code> object
     * @exception SQLException if a database access error occurs or
     * this method is called on a closed <code>Statement</code>
     * @since JDK 1.2 (JDK 1.1.x developers: read the overview
     *  for JDBCStatement)
     * @see #setFetchSize
     */
    public synchronized int getFetchSize() throws SQLException {

        checkClosed();

        return fetchSize;
    }

    /**
     * <!-- start generic documentation -->
     * Retrieves the result set concurrency for <code>ResultSet</code> objects
     * generated by this <code>Statement</code> object.
     * <!-- end generic documentation -->
     *
     * <!-- start release-specific documentation -->
     * <div class="ReleaseSpecificDocumentation">
     * <h3>HSQLDB-Specific Information:</h3> <p>
     *
     * HSQLDB supports <code>CONCUR_READ_ONLY</code> and
     * <code>CONCUR_UPDATABLE</code> concurrency.
     * </div>
     * <!-- end release-specific documentation -->
     *
     * @return either <code>ResultSet.CONCUR_READ_ONLY</code> or
     * <code>ResultSet.CONCUR_UPDATABLE</code>
     * @exception SQLException if a database access error occurs or
     * this method is called on a closed <code>Statement</code>
     * @since JDK 1.2 (JDK 1.1.x developers: read the overview
     *  for JDBCStatement)
     */
    public synchronized int getResultSetConcurrency() throws SQLException {

        checkClosed();

        return ResultProperties.getJDBCConcurrency(rsProperties);
    }

    /**
     * <!-- start generic documentation -->
     * Retrieves the result set type for <code>ResultSet</code> objects
     * generated by this <code>Statement</code> object.
     * <!-- end generic documentation -->
     *
     * <!-- start release-specific documentation -->
     * <div class="ReleaseSpecificDocumentation">
     * <h3>HSQLDB-Specific Information:</h3> <p>
     *
     * HSQLDB 1.7.0 and later versions support <code>TYPE_FORWARD_ONLY</code>
     * and <code>TYPE_SCROLL_INSENSITIVE</code>.
     * </div>
     * <!-- end release-specific documentation -->
     *
     * @return one of <code>ResultSet.TYPE_FORWARD_ONLY</code>,
     * <code>ResultSet.TYPE_SCROLL_INSENSITIVE</code>, or
     * <code>ResultSet.TYPE_SCROLL_SENSITIVE</code>
     * @exception SQLException if a database access error occurs or
     * this method is called on a closed <code>Statement</code>
     * @since JDK 1.2 (JDK 1.1.x developers: read the overview
     *   for JDBCStatement)
     */
    public synchronized int getResultSetType() throws SQLException {

        checkClosed();

        return ResultProperties.getJDBCScrollability(rsProperties);
    }

    /**
     * <!-- start generic documentation -->
     * Adds the given SQL command to the current list of commmands for this
     * <code>Statement</code> object. The commands in this list can be
     * executed as a batch by calling the method <code>executeBatch</code>.
     * <P>
     * (JDBC4 clarification:)<p>
     * <B>NOTE:</B>  Support of an ability to batch updates is optional.
     *
     * <!-- end generic documentation -->
     *
     * <!-- start release-specific documentation -->
     * <div class="ReleaseSpecificDocumentation">
     * <h3>HSQLDB-Specific Information:</h3> <p>
     *
     * Starting with 1.7.2, this feature is supported.
     * </div>
     * <!-- end release-specific documentation -->
     *
     * @param sql typically this is a SQL <code>INSERT</code> or
     * <code>UPDATE</code> statement
     * (:JDBC4 modified)
     * @exception SQLException if a database access error occurs,
     * this method is called on a closed <code>Statement</code> or the
     * driver does not support batch updates
     * @see #executeBatch
     * @since JDK 1.2 (JDK 1.1.x developers: read the overview
     *   for JDBCStatement)
     */
    public synchronized void addBatch(String sql) throws SQLException {

        checkClosed();

        if (isEscapeProcessing) {
            sql = connection.nativeSQL(sql);
        }

        if (batchResultOut == null) {
            batchResultOut = Result.newBatchedExecuteRequest();
        }
        batchResultOut.getNavigator().add(new Object[] { sql });
    }

    /**
     * <!-- start generic documentation -->
     * Empties this <code>Statement</code> object's current list of
     * SQL commands.
     * <P>
     * (JDBC4 clarification:) <p>
     * <B>NOTE:</B>  Support of an ability to batch updates is optional.
     * <!-- start generic documentation -->
     *
     * <!-- start release-specific documentation -->
     * <div class="ReleaseSpecificDocumentation">
     * <h3>HSQLDB-Specific Information:</h3> <p>
     *
     * Starting with HSQLDB 1.7.2, this feature is supported.
     * </div>
     * <!-- end release-specific documentation -->
     *
     * @exception SQLException if a database access error occurs,
     *  this method is called on a closed <code>Statement</code> or the
     * driver does not support batch updates
     * @see #addBatch
     * @since JDK 1.2 (JDK 1.1.x developers: read the overview
     *   for JDBCStatement)
     */
    public synchronized void clearBatch() throws SQLException {

        checkClosed();

        if (batchResultOut != null) {
            batchResultOut.getNavigator().clear();
        }
    }

    /**
     * <!-- start generic documentation -->
     * Submits a batch of commands to the database for execution and
     * if all commands execute successfully, returns an array of update counts.
     * The <code>int</code> elements of the array that is returned are ordered
     * to correspond to the commands in the batch, which are ordered
     * according to the order in which they were added to the batch.
     * The elements in the array returned by the method <code>executeBatch</code>
     * may be one of the following:
     * <OL>
     * <LI>A number greater than or equal to zero -- indicates that the
     * command was processed successfully and is an update count giving the
     * number of rows in the database that were affected by the command's
     * execution
     * <LI>A value of <code>SUCCESS_NO_INFO</code> -- indicates that the command was
     * processed successfully but that the number of rows affected is
     * unknown
     * <P>
     * If one of the commands in a batch update fails to execute properly,
     * this method throws a <code>BatchUpdateException</code>, and a JDBC
     * driver may or may not continue to process the remaining commands in
     * the batch.  However, the driver's behavior must be consistent with a
     * particular DBMS, either always continuing to process commands or never
     * continuing to process commands.  If the driver continues processing
     * after a failure, the array returned by the method
     * <code>BatchUpdateException.getUpdateCounts</code>
     * will contain as many elements as there are commands in the batch, and
     * at least one of the elements will be the following:
     * <P>
     * <LI>A value of <code>EXECUTE_FAILED</code> -- indicates that the command failed
     * to execute successfully and occurs only if a driver continues to
     * process commands after a command fails
     * </OL>
     * <P>
     * (JDBC4 clarification:) <p>
     * <B>NOTE:</B>  Support of an ability to batch updates is optional.
     * <p>
     * The possible implementations and return values have been modified in
     * the Java 2 SDK, Standard Edition, version 1.3 to
     * accommodate the option of continuing to proccess commands in a batch
     * update after a <code>BatchUpdateException</code> obejct has been thrown.
     * <!-- end generic documentation -->
     *
     * <!-- start release-specific documentation -->
     * <div class="ReleaseSpecificDocumentation">
     * <h3>HSQLDB-Specific Information:</h3> <p>
     *
     * Starting with HSQLDB 1.7.2, this feature is supported. <p>
     *
     * HSQLDB stops execution of commands in a batch when one of the commands
     * results in an exception. The size of the returned array equals the
     * number of commands that were executed successfully.<p>
     *
     * </div>
     * <!-- end release-specific documentation -->
     *
     * @return an array of update counts containing one element for each
     * command in the batch.  The elements of the array are ordered according
     * to the order in which commands were added to the batch.
     * @exception SQLException if a database access error occurs,
     * this method is called on a closed <code>Statement</code> or the
     * driver does not support batch statements. Throws {@link BatchUpdateException}
     * (a subclass of <code>SQLException</code>) if one of the commands sent to the
     * database fails to execute properly or attempts to return a result set.
     *
     *
     * @see #addBatch
     * @see java.sql.DatabaseMetaData#supportsBatchUpdates
     * @since JDK 1.3 (JDK 1.1.x developers: read the overview for
     * JDBCStatement)
     */
    public synchronized int[] executeBatch() throws SQLException {

        checkClosed();

        generatedResult = null;

        if (batchResultOut == null) {
            batchResultOut = Result.newBatchedExecuteRequest();
        }

        int batchCount = batchResultOut.getNavigator().getSize();

        try {
            resultIn = connection.sessionProxy.execute(batchResultOut);

            performPostExecute();
        } catch (HsqlException e) {
            batchResultOut.getNavigator().clear();

            throw JDBCUtil.sqlException(e);
        }
        batchResultOut.getNavigator().clear();

        if (resultIn.isError()) {
            throw JDBCUtil.sqlException(resultIn);
        }

        RowSetNavigator navigator    = resultIn.getNavigator();
        int[]           updateCounts = new int[navigator.getSize()];

        for (int i = 0; i < updateCounts.length; i++) {
            Object[] data = (Object[]) navigator.getNext();

            updateCounts[i] = ((Integer) data[0]).intValue();
        }

        if (updateCounts.length != batchCount) {
            if (errorResult == null) {
                throw new BatchUpdateException(updateCounts);
            } else {
                errorResult.getMainString();

                throw new BatchUpdateException(errorResult.getMainString(),
                        errorResult.getSubString(),
                        errorResult.getErrorCode(), updateCounts);
            }
        }

        return updateCounts;
    }

    /**
     * <!-- start generic documentation -->
     * Retrieves the <code>Connection</code> object
     * that produced this <code>Statement</code> object.
     * <!-- end generic documentation -->
     *
     * @return the connection that produced this statement
     * @exception SQLException if a database access error occurs or
     * this method is called on a closed <code>Statement</code>
     * @since JDK 1.2 (JDK 1.1.x developers: read the overview
     *    for JDBCStatement)
     */
    public synchronized Connection getConnection() throws SQLException {

        checkClosed();

        return connection;
    }

    //--------------------------JDBC 3.0-----------------------------

    /**
     * <!-- start generic documentation -->
     * Moves to this <code>Statement</code> object's next result, deals with
     * any current <code>ResultSet</code> object(s) according  to the instructions
     * specified by the given flag, and returns
     * <code>true</code> if the next result is a <code>ResultSet</code> object.
     *
     * <P>There are no more results when the following is true:
     * <PRE>
     *     // stmt is a Statement object
     *     ((stmt.getMoreResults(current) == false) && (stmt.getUpdateCount() == -1))
     * </PRE>
     * <!-- end generic documentation -->
     *
     * <!-- start release-specific documentation -->
     * <div class="ReleaseSpecificDocumentation">
     * <h3>HSQLDB-Specific Information:</h3> <p>
     *
     * HSQLDB moves to the next ResultSet and returns the correct result. <p>
     * </div>
     * <!-- end release-specific documentation -->
     *
     * @param current one of the following <code>Statement</code>
     *        constants indicating what should happen to current
     *        <code>ResultSet</code> objects obtained using the method
     *        <code>getResultSet</code>:
     *        <code>Statement.CLOSE_CURRENT_RESULT</code>,
     *        <code>Statement.KEEP_CURRENT_RESULT</code>, or
     *        <code>Statement.CLOSE_ALL_RESULTS</code>
     * @return <code>true</code> if the next result is a <code>ResultSet</code>
     *         object; <code>false</code> if it is an update count or there are no
     *         more results
     * @exception SQLException if a database access error occurs,
     * this method is called on a closed <code>Statement</code> or the argument
     *             supplied is not one of the following:
     *        <code>Statement.CLOSE_CURRENT_RESULT</code>,
     *        <code>Statement.KEEP_CURRENT_RESULT</code>, or
     *        <code>Statement.CLOSE_ALL_RESULTS</code>
     * @since JDK 1.4, HSQLDB 1.7
     * @see #execute
     */
//#ifdef JAVA4
    public synchronized boolean getMoreResults(
            int current) throws SQLException {
        return super.getMoreResults(current);
    }

//#endif JAVA4

    /**
     * <!-- start generic documentation -->
     * Retrieves any auto-generated keys created as a result of executing this
     * <code>Statement</code> object. If this <code>Statement</code> object did
     * not generate any keys, an empty <code>ResultSet</code>
     * object is returned.
     * <p>(JDBC4 clarification:)
     * <p><B>Note:</B>If the columns which represent the auto-generated keys were not specified,
     * the JDBC driver implementation will determine the columns which best represent the auto-generated keys.
     * <!-- end generic documentation -->
     *
     * <!-- start release-specific documentation -->
     * <div class="ReleaseSpecificDocumentation">
     * <h3>HSQLDB-Specific Information:</h3> <p>
     *
     * Starting with version 2.0, HSQLDB supports this feature with single-row
     * and multi-row insert, update and merge statements. <p>
     *
     * This method returns a result set only if
     * the executeUpdate methods that was used is one of the three methods that
     * have the extra parameter indicating return of generated keys<p>
     *
     * If the executeUpaged method did not specify the columns which represent
     * the auto-generated keys the IDENTITY column or GENERATED column(s) of the
     * table are returned.<p>
     *
     * The executeUpdate methods with column indexes or column names return the
     * post-insert or post-update values of the specified columns, whether the
     * columns are generated or not. This allows values that have been modified
     * by execution of triggers to be returned.<p>
     *
     * If column names or indexes provided by the user in the executeUpdate()
     * method calls do not correspond to table columns (incorrect names or
     * indexes larger than the coloum count), an empty result is returned.
     *
     * </div>
     * <!-- end release-specific documentation -->
     *
     * @return a <code>ResultSet</code> object containing the auto-generated key(s)
     *         generated by the execution of this <code>Statement</code> object
     * @exception SQLException if a database access error occurs or
     * this method is called on a closed <code>Statement</code>
     * @throws SQLFeatureNotSupportedException  if the JDBC driver does not support this method
     * @since JDK 1.4, HSQLDB 1.7
     */
//#ifdef JAVA4
    public synchronized ResultSet getGeneratedKeys() throws SQLException {
        return getGeneratedResultSet();
    }

//#endif JAVA4

    /**
     * <!-- start generic documentation -->
     * Executes the given SQL statement and signals the driver with the
     * given flag about whether the
     * auto-generated keys produced by this <code>Statement</code> object
     * should be made available for retrieval.  The driver will ignore the
     * flag if the SQL statement
     * is not an <code>INSERT</code> statement, or an SQL statement able to return
     * auto-generated keys (the list of such statements is vendor-specific).
     * <!-- end generic documentation -->
     *
     * <!-- start release-specific documentation -->
     * <div class="ReleaseSpecificDocumentation">
     * <h3>HSQLDB-Specific Information:</h3> <p>
     *
     * Starting with version 2.0, HSQLDB supports returning generated columns
     * with single-row and multi-row INSERT, UPDATE and MERGE statements. <p>
     * If the table has an IDENTITY or GENERATED column(s) the values for these
     * columns are returned in the next call to getGeneratedKeys().
     *
     * </div>
     * <!-- end release-specific documentation -->
     * @param sql an SQL Data Manipulation Language (DML) statement, such as <code>INSERT</code>, <code>UPDATE</code> or
     * <code>DELETE</code>; or an SQL statement that returns nothing,
     * such as a DDL statement.
     * (:JDBC4 clarification)
     *
     * @param autoGeneratedKeys a flag indicating whether auto-generated keys
     *        should be made available for retrieval;
     *         one of the following constants:
     *         <code>Statement.RETURN_GENERATED_KEYS</code>
     *         <code>Statement.NO_GENERATED_KEYS</code>
     * @return either (1) the row count for SQL Data Manipulation Language (DML) statements
     *         or (2) 0 for SQL statements that return nothing
     *         (:JDBC4 clarification)
     *
     * @exception SQLException if a database access error occurs,
     *  this method is called on a closed <code>Statement</code>, the given
     *            SQL statement returns a <code>ResultSet</code> object, or
     *            the given constant is not one of those allowed
     * @exception SQLFeatureNotSupportedException if the JDBC driver does not support
     * this method with a constant of Statement.RETURN_GENERATED_KEYS
     * @since JDK 1.4, HSQLDB 1.7
     */
//#ifdef JAVA4
    public synchronized int executeUpdate(String sql,
            int autoGeneratedKeys) throws SQLException {

        if (autoGeneratedKeys != Statement.RETURN_GENERATED_KEYS
                && autoGeneratedKeys != Statement.NO_GENERATED_KEYS) {
            throw JDBCUtil.invalidArgument("autoGeneratedKeys");
        }
        fetchResult(sql, StatementTypes.RETURN_COUNT, autoGeneratedKeys, null,
                    null);

        if (resultIn.isError()) {
            throw JDBCUtil.sqlException(resultIn);
        }

        return resultIn.getUpdateCount();
    }

//#endif JAVA4

    /**
     * <!-- start generic documentation -->
     * Executes the given SQL statement and signals the driver that the
     * auto-generated keys indicated in the given array should be made available
     * for retrieval.  The driver will ignore the array if the SQL statement
     * is not an <code>INSERT</code> statement, or an SQL statement able to return
     * (JDBC 4 clarification)
     * auto-generated keys (the list of such statements is vendor-specific).
     * <!-- end generic documentation -->
     *
     * <!-- start release-specific documentation -->
     * <div class="ReleaseSpecificDocumentation">
     * <h3>HSQLDB-Specific Information:</h3> <p>
     *
     * Starting with version 2.0, HSQLDB supports returning generated columns
     * with single-row and multi-row INSERT, UPDATE and MERGE statements. <p>
     * The columnIndexes may specify any set of columns of the table.
     *
     * </div>
     * <!-- end release-specific documentation -->
     *
     * @param sql an SQL Data Manipulation Language (DML) statement, such as <code>INSERT</code>, <code>UPDATE</code> or
     * <code>DELETE</code>; or an SQL statement that returns nothing,
     * such as a DDL statement.
     * (:JDBC4 clarification)
     *
     * @param columnIndexes an array of column indexes indicating the columns
     *        that should be returned from the inserted row
     * @return either (1) the row count for SQL Data Manipulation Language (DML) statements
     *         or (2) 0 for SQL statements that return nothing
     *         (:JDBC 4 clarification)
     *
     * @exception SQLException if a database access error occurs,
     * this method is called on a closed <code>Statement</code>, the SQL
     *            statement returns a <code>ResultSet</code> object, or the
     *            second argument supplied to this method is not an <code>int</code> array
     *            whose elements are valid column indexes
     * @throws SQLFeatureNotSupportedException  if the JDBC driver does not support this method
     * @since JDK 1.4, HSQLDB 1.7
     */
//#ifdef JAVA4
    public synchronized int executeUpdate(String sql,
            int[] columnIndexes) throws SQLException {

        if (columnIndexes == null || columnIndexes.length == 0) {
            throw JDBCUtil.invalidArgument("columnIndexes");
        }
        fetchResult(sql, StatementTypes.RETURN_COUNT,
                    ResultConstants.RETURN_GENERATED_KEYS_COL_INDEXES,
                    columnIndexes, null);

        return resultIn.getUpdateCount();
    }

//#endif JAVA4

    /**
     * <!-- start generic documentation -->
     * Executes the given SQL statement and signals the driver that the
     * auto-generated keys indicated in the given array should be made available
     * for retrieval.   The driver will ignore the array if the SQL statement
     * (JDBC4 clarification:)
     * is not an <code>INSERT</code> statement, or an SQL statement able to return
     * auto-generated keys (the list of such statements is vendor-specific).
     * <!-- end generic documentation -->
     *
     * <!-- start release-specific documentation -->
     * <div class="ReleaseSpecificDocumentation">
     * <h3>HSQLDB-Specific Information:</h3> <p>
     *
     * Starting with version 2.0, HSQLDB supports returning generated columns
     * with single-row and multi-row INSERT, UPDATE and MERGE statements. <p>
     * The columnNames may specify any set of columns of the table.
     *
     * </div>
     * <!-- end release-specific documentation -->
     *
     * @param sql an SQL Data Manipulation Language (DML) statement, such as <code>INSERT</code>, <code>UPDATE</code> or
     * <code>DELETE</code>; or an SQL statement that returns nothing,
     * such as a DDL statement.
     * (:JDBC4 clarification)
     * @param columnNames an array of the names of the columns that should be
     *        returned from the inserted row
     * @return either the row count for <code>INSERT</code>, <code>UPDATE</code>,
     *         or <code>DELETE</code> statements, or 0 for SQL statements
     *         that return nothing
     * @exception SQLException if a database access error occurs,
     *  this method is called on a closed <code>Statement</code>, the SQL
     *            statement returns a <code>ResultSet</code> object, or the
     *            second argument supplied to this method is not a <code>String</code> array
     *            whose elements are valid column names
     *
     * @throws SQLFeatureNotSupportedException  if the JDBC driver does not support this method
     * @since JDK 1.4, HSQLDB 1.7
     */
//#ifdef JAVA4
    public synchronized int executeUpdate(String sql,
            String[] columnNames) throws SQLException {

        if (columnNames == null || columnNames.length == 0) {
            throw JDBCUtil.invalidArgument("columnIndexes");
        }
        fetchResult(sql, StatementTypes.RETURN_COUNT,
                    ResultConstants.RETURN_GENERATED_KEYS_COL_NAMES, null,
                    columnNames);

        return resultIn.getUpdateCount();
    }

//#endif JAVA4

    /**
     * <!-- start generic documentation -->
     * Executes the given SQL statement, which may return multiple results,
     * and signals the driver that any
     * auto-generated keys should be made available
     * for retrieval.  The driver will ignore this signal if the SQL statement
     * is not an <code>INSERT</code> statement, or an SQL statement able to return
     * (JDBC4 clarification)
     * auto-generated keys (the list of such statements is vendor-specific).
     * <P>
     * In some (uncommon) situations, a single SQL statement may return
     * multiple result sets and/or update counts.  Normally you can ignore
     * this unless you are (1) executing a stored procedure that you know may
     * return multiple results or (2) you are dynamically executing an
     * unknown SQL string.
     * <P>
     * The <code>execute</code> method executes an SQL statement and indicates the
     * form of the first result.  You must then use the methods
     * <code>getResultSet</code> or <code>getUpdateCount</code>
     * to retrieve the result, and <code>getMoreResults</code> to
     * move to any subsequent result(s).
     * <!-- end generic documentation -->
     *
     * <!-- start release-specific documentation -->
     * <div class="ReleaseSpecificDocumentation">
     * <h3>HSQLDB-Specific Information:</h3> <p>
     *
     * Starting with 2.0, HSQLDB supports this feature.
     *
     * </div>
     * <!-- end release-specific documentation -->
     *
     * @param sql any SQL statement
     * @param autoGeneratedKeys a constant indicating whether auto-generated
     *        keys should be made available for retrieval using the method
     *        <code>getGeneratedKeys</code>; one of the following constants:
     *        <code>Statement.RETURN_GENERATED_KEYS</code> or
     *        <code>Statement.NO_GENERATED_KEYS</code>
     * @return <code>true</code> if the first result is a <code>ResultSet</code>
     *         object; <code>false</code> if it is an update count or there are
     *         no results
     * @exception SQLException if a database access error occurs,
     * this method is called on a closed <code>Statement</code> or the second
     *         parameter supplied to this method is not
     *         <code>Statement.RETURN_GENERATED_KEYS</code> or
     *         <code>Statement.NO_GENERATED_KEYS</code>.
     * @exception SQLFeatureNotSupportedException if the JDBC driver does not support
     * this method with a constant of Statement.RETURN_GENERATED_KEYS
     * @see #getResultSet
     * @see #getUpdateCount
     * @see #getMoreResults
     * @see #getGeneratedKeys
     * @since JDK 1.4, HSQLDB 1.7
     */
//#ifdef JAVA4
    public synchronized boolean execute(
            String sql, int autoGeneratedKeys) throws SQLException {

        if (autoGeneratedKeys != Statement.RETURN_GENERATED_KEYS
                && autoGeneratedKeys != Statement.NO_GENERATED_KEYS) {
            throw JDBCUtil.invalidArgument("autoGeneratedKeys");
        }
        fetchResult(sql, StatementTypes.RETURN_ANY, autoGeneratedKeys, null,
                    null);

        return resultIn.isData();
    }

//#endif JAVA4

    /**
     * <!-- start generic documentation -->
     * Executes the given SQL statement, which may return multiple results,
     * and signals the driver that the
     * auto-generated keys indicated in the given array should be made available
     * for retrieval.  This array contains the indexes of the columns in the
     * target table that contain the auto-generated keys that should be made
     * available.  The driver will ignore the array if the SQL statement
     * (JDBC4 clarification)
     * is not an <code>INSERT</code> statement, or an SQL statement able to return
     * auto-generated keys (the list of such statements is vendor-specific).
     * <P>
     * Under some (uncommon) situations, a single SQL statement may return
     * multiple result sets and/or update counts.  Normally you can ignore
     * this unless you are (1) executing a stored procedure that you know may
     * return multiple results or (2) you are dynamically executing an
     * unknown SQL string.
     * <P>
     * The <code>execute</code> method executes an SQL statement and indicates the
     * form of the first result.  You must then use the methods
     * <code>getResultSet</code> or <code>getUpdateCount</code>
     * to retrieve the result, and <code>getMoreResults</code> to
     * move to any subsequent result(s).
     * <!-- end generic documentation -->
     *
     * <!-- start release-specific documentation -->
     * <div class="ReleaseSpecificDocumentation">
     * <h3>HSQLDB-Specific Information:</h3> <p>
     *
     * Starting with 2.0, HSQLDB supports this feature.
     *
     * </div>
     * <!-- end release-specific documentation -->
     *
     * @param sql any SQL statement
     * @param columnIndexes an array of the indexes of the columns in the
     *        inserted row that should be  made available for retrieval by a
     *        call to the method <code>getGeneratedKeys</code>
     * @return <code>true</code> if the first result is a <code>ResultSet</code>
     *         object; <code>false</code> if it is an update count or there
     *         are no results
     * @exception SQLException if a database access error occurs,
     * this method is called on a closed <code>Statement</code> or the
     *            elements in the <code>int</code> array passed to this method
     *            are not valid column indexes
     * @throws SQLFeatureNotSupportedException  if the JDBC driver does not support this method
     * @see #getResultSet
     * @see #getUpdateCount
     * @see #getMoreResults
     * @since JDK 1.4, HSQLDB 1.7
     */
//#ifdef JAVA4
    public synchronized boolean execute(
            String sql, int[] columnIndexes) throws SQLException {

        if (columnIndexes == null || columnIndexes.length == 0) {
            throw JDBCUtil.invalidArgument("columnIndexes");
        }
        fetchResult(sql, StatementTypes.RETURN_ANY,
                    ResultConstants.RETURN_GENERATED_KEYS_COL_INDEXES,
                    columnIndexes, null);

        return resultIn.isData();
    }

//#endif JAVA4

    /**
     * <!-- start generic documentation -->
     * Executes the given SQL statement, which may return multiple results,
     * and signals the driver that the
     * auto-generated keys indicated in the given array should be made available
     * for retrieval. This array contains the names of the columns in the
     * target table that contain the auto-generated keys that should be made
     * available.  The driver will ignore the array if the SQL statement
     * is not an <code>INSERT</code> statement, or an SQL statement able to return
     * auto-generated keys (the list of such statements is vendor-specific).
     * <P>
     * In some (uncommon) situations, a single SQL statement may return
     * multiple result sets and/or update counts.  Normally you can ignore
     * this unless you are (1) executing a stored procedure that you know may
     * return multiple results or (2) you are dynamically executing an
     * unknown SQL string.
     * <P>
     * The <code>execute</code> method executes an SQL statement and indicates the
     * form of the first result.  You must then use the methods
     * <code>getResultSet</code> or <code>getUpdateCount</code>
     * to retrieve the result, and <code>getMoreResults</code> to
     * move to any subsequent result(s).
     * <!-- end generic documentation -->
     *
     * <!-- start release-specific documentation -->
     * <div class="ReleaseSpecificDocumentation">
     * <h3>HSQLDB-Specific Information:</h3> <p>
     *
     * Starting with 2.0, HSQLDB supports this feature.
     *
     * </div>
     * <!-- end release-specific documentation -->
     *
     * @param sql any SQL statement
     * @param columnNames an array of the names of the columns in the inserted
     *        row that should be made available for retrieval by a call to the
     *        method <code>getGeneratedKeys</code>
     * @return <code>true</code> if the next result is a <code>ResultSet</code>
     *         object; <code>false</code> if it is an update count or there
     *         are no more results
     * @exception SQLException if a database access error occurs,
     * this method is called on a closed <code>Statement</code> or the
     *          elements of the <code>String</code> array passed to this
     *          method are not valid column names
     * @throws SQLFeatureNotSupportedException  if the JDBC driver does not support this method
     * @see #getResultSet
     * @see #getUpdateCount
     * @see #getMoreResults
     * @see #getGeneratedKeys
     * @since JDK 1.4, HSQLDB 1.7
     */
//#ifdef JAVA4
    public synchronized boolean execute(
            String sql, String[] columnNames) throws SQLException {

        if (columnNames == null || columnNames.length == 0) {
            throw JDBCUtil.invalidArgument("columnIndexes");
        }
        fetchResult(sql, StatementTypes.RETURN_ANY,
                    ResultConstants.RETURN_GENERATED_KEYS_COL_NAMES, null,
                    columnNames);

        return resultIn.isData();
    }

//#endif JAVA4

    /**
     * <!-- start generic documentation -->
     * Retrieves the result set holdability for <code>ResultSet</code> objects
     * generated by this <code>Statement</code> object.
     * <!-- end generic documentation -->
     *
     * @return either <code>ResultSet.HOLD_CURSORS_OVER_COMMIT</code> or
     *         <code>ResultSet.CLOSE_CURSORS_AT_COMMIT</code>
     * @exception SQLException if a database access error occurs or
     * this method is called on a closed <code>Statement</code>
     * @since JDK 1.4, HSQLDB 1.7
     */
//#ifdef JAVA4
    public synchronized int getResultSetHoldability() throws SQLException {
        return ResultProperties.getJDBCHoldability(rsProperties);
    }

//#endif JAVA4
    //----------------------------- JDBC 4.0 -----------------------------------

    /**
     * Retrieves whether this <code>Statement</code> object has been closed. A <code>Statement</code> is closed if the
     * method close has been called on it, or if it is automatically closed.
     * @return true if this <code>Statement</code> object is closed; false if it is still open
     * @throws SQLException if a database access error occurs
     * @since JDK 1.6, HSQLDB 2.0
     */
    public synchronized boolean isClosed() throws SQLException {
        return isClosed;
    }

// --------------------------- Added: Mustang Build 81 -------------------------
    boolean poolable = false;

    /**
     * Requests that a <code>Statement</code> be pooled or not pooled.  The value
     * specified is a hint to the statement pool implementation indicating
     * whether the applicaiton wants the statement to be pooled.  It is up to
     * the statement pool manager as to whether the hint is used.
     * <p>
     * The poolable value of a statement is applicable to both internal
     * statement caches implemented by the driver and external statement caches
     * implemented by application servers and other applications.
     * <p>
     * By default, a <code>Statement</code> is not poolable when created, and
     * a <code>PreparedStatement</code> and <code>CallableStatement</code>
     * are poolable when created.
     * <p>
     * @param poolable          requests that the statement be pooled if true and
     *                                          that the statement not be pooled if false
     * <p>
     * @throws SQLException if this method is called on a closed
     * <code>Statement</code>
     * <p>
     * @since JDK 1.6 Build 81, HSQLDB 2.0
     */

//#ifdef JAVA6
    public synchronized void setPoolable(
            boolean poolable) throws SQLException {

        checkClosed();

        this.poolable = poolable;
    }

//#endif JAVA6

    /**
     * Returns a  value indicating whether the <code>Statement</code>
     * is poolable or not.
     * <p>
     * @return          <code>true</code> if the <code>Statement</code>
     * is poolable; <code>false</code> otherwise
     * @throws SQLException if this method is called on a closed
     * <code>Statement</code>
     * <p>
     * @since JDK 1.6 Build 81, HSQLDB 2.0
     * <p>
     * @see #setPoolable(boolean) setPoolable(boolean)
     */
//#ifdef JAVA6
    public synchronized boolean isPoolable() throws SQLException {

        checkClosed();

        return this.poolable;
    }

//#endif JAVA6
    // ------------------- java.sql.Wrapper implementation ---------------------

    /**
     * Returns an object that implements the given interface to allow access to
     * non-standard methods, or standard methods not exposed by the proxy.
     *
     * If the receiver implements the interface then the result is the receiver
     * or a proxy for the receiver. If the receiver is a wrapper
     * and the wrapped object implements the interface then the result is the
     * wrapped object or a proxy for the wrapped object. Otherwise return the
     * the result of calling <code>unwrap</code> recursively on the wrapped object
     * or a proxy for that result. If the receiver is not a
     * wrapper and does not implement the interface, then an <code>SQLException</code> is thrown.
     *
     * @param iface A Class defining an interface that the result must implement.
     * @return an object that implements the interface. May be a proxy for the actual implementing object.
     * @throws SQLException If no object found that implements the interface
     * @since JDK 1.6, HSQLDB 2.0
     */
//#ifdef JAVA6
    @SuppressWarnings("unchecked")
    public <T>T unwrap(Class<T> iface) throws SQLException {

        if (isWrapperFor(iface)) {
            return (T) this;
        }

        throw JDBCUtil.invalidArgument("iface: " + iface);
    }

//#endif JAVA6

    /**
     * Returns true if this either implements the interface argument or is directly or indirectly a wrapper
     * for an object that does. Returns false otherwise. If this implements the interface then return true,
     * else if this is a wrapper then return the result of recursively calling <code>isWrapperFor</code> on the wrapped
     * object. If this does not implement the interface and is not a wrapper, return false.
     * This method should be implemented as a low-cost operation compared to <code>unwrap</code> so that
     * callers can use this method to avoid expensive <code>unwrap</code> calls that may fail. If this method
     * returns true then calling <code>unwrap</code> with the same argument should succeed.
     *
     * @param iface a Class defining an interface.
     * @return true if this implements the interface or directly or indirectly wraps an object that does.
     * @throws SQLException  if an error occurs while determining whether this is a wrapper
     * for an object with the given interface.
     * @since JDK 1.6, HSQLDB 2.0
     */
//#ifdef JAVA6
    public boolean isWrapperFor(
            Class<?> iface) throws SQLException {
        return (iface != null && iface.isAssignableFrom(this.getClass()));
    }

//#endif JAVA6
    // -------------------- Internal Implementation ----------------------------

    /**
     * Constructs a new JDBCStatement with the specified connection and result
     * type.
     *
     * @param c the connection on which this statement will execute
     */
    JDBCStatement(JDBCConnection c, int props) {

        resultOut             = Result.newExecuteDirectRequest();
        connection            = c;
        connectionIncarnation = connection.incarnation;
        rsProperties          = props;
    }

    /**
     * Internal result producer for JDBCStatement (sqlExecDirect mode).
     *
     * <p>
     *
     * @param sql a character sequence representing the SQL to be executed
     * @param statementRetType int
     * @param generatedKeys int
     * @param generatedIndexes int[]
     * @param generatedNames String[]
     * @throws SQLException when a database access error occurs
     */
    private void fetchResult(String sql, int statementRetType,
                             int generatedKeys, int[] generatedIndexes,
                             String[] generatedNames) throws SQLException {

        checkClosed();
        closeResultData();

        if (isEscapeProcessing) {
            sql = connection.nativeSQL(sql);
        }
        resultOut.setPrepareOrExecuteProperties(sql, maxRows, fetchSize,
                statementRetType, queryTimeout, rsProperties, generatedKeys,
                generatedIndexes, generatedNames);

        try {
            resultIn = connection.sessionProxy.execute(resultOut);

            performPostExecute();
        } catch (HsqlException e) {
            throw JDBCUtil.sqlException(e);
        }

        if (resultIn.isError()) {
            throw JDBCUtil.sqlException(resultIn);
        }

        if (resultIn.isData()) {
            currentResultSet = new JDBCResultSet(connection, this, resultIn,
                    resultIn.metaData);
        } else if (resultIn.getStatementType()
                   == StatementTypes.RETURN_RESULT) {
            getMoreResults();
        }
    }
}
